Browse Source
Instead of traversing the tree while raising an event, instead first build an event route and then raise the event along it. Fixes #3176pull/3621/head
Steven Kirk
6 years ago
7 changed files with 266 additions and 147 deletions
@ -0,0 +1,200 @@ |
|||
using System; |
|||
using Avalonia.Collections.Pooled; |
|||
|
|||
namespace Avalonia.Interactivity |
|||
{ |
|||
/// <summary>
|
|||
/// Holds the route for a routed event and supports raising an event on that route.
|
|||
/// </summary>
|
|||
public class EventRoute : IDisposable |
|||
{ |
|||
private readonly RoutedEvent _event; |
|||
private PooledList<RouteItem>? _route; |
|||
|
|||
/// <summary>
|
|||
/// Initializes a new instance of the <see cref="RoutedEvent"/> class.
|
|||
/// </summary>
|
|||
/// <param name="e">The routed event to be raised.</param>
|
|||
public EventRoute(RoutedEvent e) |
|||
{ |
|||
e = e ?? throw new ArgumentNullException(nameof(e)); |
|||
|
|||
_event = e; |
|||
_route = null; |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Gets a value indicating whether the route has any handlers.
|
|||
/// </summary>
|
|||
public bool HasHandlers => _route?.Count > 0; |
|||
|
|||
/// <summary>
|
|||
/// Adds a handler to the route.
|
|||
/// </summary>
|
|||
/// <param name="target">The target on which the event should be raised.</param>
|
|||
/// <param name="handler">The handler for the event.</param>
|
|||
/// <param name="routes">The routing strategies to listen to.</param>
|
|||
/// <param name="handledEventsToo">
|
|||
/// If true the handler will be raised even when the routed event is marked as handled.
|
|||
/// </param>
|
|||
/// <param name="adapter">
|
|||
/// An optional adapter which if supplied, will be called with <paramref name="handler"/>
|
|||
/// and the parameters for the event. This adapter can be used to avoid calling
|
|||
/// `DynamicInvoke` on the handler.
|
|||
/// </param>
|
|||
public void Add( |
|||
IInteractive target, |
|||
Delegate handler, |
|||
RoutingStrategies routes, |
|||
bool handledEventsToo = false, |
|||
Action<Delegate, object, RoutedEventArgs>? adapter = null) |
|||
{ |
|||
target = target ?? throw new ArgumentNullException(nameof(target)); |
|||
handler = handler ?? throw new ArgumentNullException(nameof(handler)); |
|||
|
|||
_route ??= new PooledList<RouteItem>(16); |
|||
_route.Add(new RouteItem(target, handler, adapter, routes, handledEventsToo)); |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Adds a class handler to the route.
|
|||
/// </summary>
|
|||
/// <param name="target">The target on which the event should be raised.</param>
|
|||
public void AddClassHandler(IInteractive target) |
|||
{ |
|||
target = target ?? throw new ArgumentNullException(nameof(target)); |
|||
|
|||
_route ??= new PooledList<RouteItem>(16); |
|||
_route.Add(new RouteItem(target, null, null, 0, false)); |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Raises an event along the route.
|
|||
/// </summary>
|
|||
/// <param name="source">The event source.</param>
|
|||
/// <param name="e">The event args.</param>
|
|||
public void RaiseEvent(IInteractive source, RoutedEventArgs e) |
|||
{ |
|||
source = source ?? throw new ArgumentNullException(nameof(source)); |
|||
e = e ?? throw new ArgumentNullException(nameof(e)); |
|||
|
|||
e.Source = source; |
|||
|
|||
if (_event.RoutingStrategies == RoutingStrategies.Direct) |
|||
{ |
|||
e.Route = RoutingStrategies.Direct; |
|||
RaiseEventImpl(e); |
|||
_event.InvokeRouteFinished(e); |
|||
} |
|||
else |
|||
{ |
|||
if (_event.RoutingStrategies.HasFlagCustom(RoutingStrategies.Tunnel)) |
|||
{ |
|||
e.Route = RoutingStrategies.Tunnel; |
|||
RaiseEventImpl(e); |
|||
_event.InvokeRouteFinished(e); |
|||
} |
|||
|
|||
if (_event.RoutingStrategies.HasFlagCustom(RoutingStrategies.Bubble)) |
|||
{ |
|||
e.Route = RoutingStrategies.Bubble; |
|||
RaiseEventImpl(e); |
|||
_event.InvokeRouteFinished(e); |
|||
} |
|||
} |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Disposes of the event route.
|
|||
/// </summary>
|
|||
public void Dispose() |
|||
{ |
|||
_route?.Dispose(); |
|||
_route = null; |
|||
} |
|||
|
|||
private void RaiseEventImpl(RoutedEventArgs e) |
|||
{ |
|||
if (_route is null) |
|||
{ |
|||
return; |
|||
} |
|||
|
|||
if (e.Source is null) |
|||
{ |
|||
throw new ArgumentException("Event source may not be null", nameof(e)); |
|||
} |
|||
|
|||
IInteractive? lastTarget = null; |
|||
var start = 0; |
|||
var end = _route.Count; |
|||
var step = 1; |
|||
|
|||
if (e.Route == RoutingStrategies.Tunnel) |
|||
{ |
|||
start = end - 1; |
|||
step = end = -1; |
|||
} |
|||
|
|||
for (var i = start; i != end; i += step) |
|||
{ |
|||
var entry = _route[i]; |
|||
|
|||
// If we've got to a new control then call any RoutedEvent.Raised listeners.
|
|||
if (entry.Target != lastTarget) |
|||
{ |
|||
if (!e.Handled) |
|||
{ |
|||
_event.InvokeRaised(entry.Target, e); |
|||
} |
|||
|
|||
// If this is a direct event and we've already raised events then we're finished.
|
|||
if (e.Route == RoutingStrategies.Direct && lastTarget is object) |
|||
{ |
|||
return; |
|||
} |
|||
|
|||
lastTarget = entry.Target; |
|||
} |
|||
|
|||
// Raise the event handler.
|
|||
if (entry.Handler is object && |
|||
entry.Routes.HasFlagCustom(e.Route) && |
|||
(!e.Handled || entry.HandledEventsToo)) |
|||
{ |
|||
if (entry.Adapter is object) |
|||
{ |
|||
entry.Adapter(entry.Handler, entry.Target, e); |
|||
} |
|||
else |
|||
{ |
|||
entry.Handler.DynamicInvoke(entry.Target, e); |
|||
} |
|||
} |
|||
} |
|||
} |
|||
|
|||
private readonly struct RouteItem |
|||
{ |
|||
public RouteItem( |
|||
IInteractive target, |
|||
Delegate? handler, |
|||
Action<Delegate, object, RoutedEventArgs>? adapter, |
|||
RoutingStrategies routes, |
|||
bool handledEventsToo) |
|||
{ |
|||
Target = target; |
|||
Handler = handler; |
|||
Adapter = adapter; |
|||
Routes = routes; |
|||
HandledEventsToo = handledEventsToo; |
|||
} |
|||
|
|||
public IInteractive Target { get; } |
|||
public Delegate? Handler { get; } |
|||
public Action<Delegate, object, RoutedEventArgs>? Adapter { get; } |
|||
public RoutingStrategies Routes { get; } |
|||
public bool HandledEventsToo { get; } |
|||
} |
|||
} |
|||
} |
|||
Loading…
Reference in new issue